Combining polymeric devices and stem cells for the treatment of neurological disorders: a promising therapeutic approach.

Cell therapy will probably become a major therapeutic strategy for neuronal disorders in the coming years. Nevertheless, due to poor survival of grafted cells and limited differentiation and integration in the host tissue, certain ameliorations must be envisaged. To address these difficulties, several strategies have been developed and among them, two methods seem particularly promising : in situ controlled drug delivery and implantation of cells adhered on biomaterial-based scaffolds. Indeed, the ability of drugs, such as growth factors, to regulate neuronal survival and/or plasticity infers the use of these molecules to treat neurodegeneration associated with human diseases. Moreover, the synthesis of cell scaffolds which mimic the extra-cellular matrix can help guide morphogenesis and tissue repair. Furthermore, cells can be cultivated on these matrices that may eventually make graft therapy a more practical approach for the treatment of neurological diseases. Nevertheless, for those two encouraging approaches multiple parameters have to be considered, such as the drug targeting strategy, but also the physical and morphological characteristics of the scaffold and the type of cells to be conveyed. This review thus focuses on those two promising strategies and also on their possible association to improve stem cell therapy of neurodegenerative disorders. Indeed, tissue replacement by grafting cells within or adhered onto drug delivering biomaterial-based devices, has recently been reported and seems to be very promising.